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authorLinus Torvalds <torvalds@linux-foundation.org>2025-05-26 14:20:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2025-05-26 14:20:50 -0700
commit07046958f6ddaa1e05ac64d1e11e77b6db9a00ce (patch)
tree09cf917294cf322c8c9d08e0d54786ef8ae20d2c /Documentation
parentMerge tag 'tpmdd-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd (diff)
parentMerge branches 'rcu/misc-for-6.16', 'rcu/seq-counters-for-6.16' and 'rcu/torture-for-6.16' into rcu/for-next (diff)
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Merge tag 'next.2025.05.17a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux
Pull RCU updates from Joel Fernandes: - Removed swake_up_one_online() workaround - Reverted an incorrect rcuog wake-up fix from offline softirq - Rust RCU Guard methods marked as inline - Updated MAINTAINERS with Joel’s and Zqiang's new email address - Replaced magic constant in rcu_seq_done_exact() with named constant - Added warning mechanism to validate rcu_seq_done_exact() - Switched SRCU polling API to use rcu_seq_done_exact() - Commented on redundant delta check in rcu_seq_done_exact() - Made ->gpwrap tests in rcutorture more frequent - Fixed reuse of ARM64 images in rcutorture - rcutorture improved to check Kconfig and reader conflict handling - Extracted logic from rcu_torture_one_read() for clarity - Updated LWN RCU API documentation links - Enabled --do-rt in torture.sh for CONFIG_PREEMPT_RT - Added tests for SRCU up/down reader primitives - Added comments and delays checks in rcutorture - Deprecated srcu_read_lock_lite() and srcu_read_unlock_lite() via checkpatch - Added --do-normal and --do-no-normal to torture.sh - Added RCU Rust binding tests to torture.sh - Reduced CPU overcommit and removed MAXSMP/CPUMASK_OFFSTACK in TREE01 - Replaced kmalloc() with kcalloc() in rcuscale - Refined listRCU example code for stale data elimination - Fixed hardirq count bug for x86 in cpu_stall_cputime - Added safety checks in rcu/nocb for offloaded rdp access - Other miscellaneous changes * tag 'next.2025.05.17a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (27 commits) rcutorture: Fix issue with re-using old images on ARM64 rcutorture: Remove MAXSMP and CPUMASK_OFFSTACK from TREE01 rcutorture: Reduce TREE01 CPU overcommit torture: Check for "Call trace:" as well as "Call Trace:" rcutorture: Perform more frequent testing of ->gpwrap torture: Add testing of RCU's Rust bindings to torture.sh torture: Add --do-{,no-}normal to torture.sh checkpatch: Deprecate srcu_read_lock_lite() and srcu_read_unlock_lite() rcutorture: Comment invocations of tick_dep_set_task() rcu/nocb: Add Safe checks for access offloaded rdp rcuscale: using kcalloc() to relpace kmalloc() doc/RCU/listRCU: refine example code for eliminating stale data doc: Update LWN RCU API links in whatisRCU.rst Revert "rcu/nocb: Fix rcuog wake-up from offline softirq" rust: sync: rcu: Mark Guard methods as inline rcu/cpu_stall_cputime: fix the hardirq count for x86 architecture rcu: Remove swake_up_one_online() bandaid MAINTAINERS: Update Zqiang's email address rcutorture: Make torture.sh --do-rt use CONFIG_PREEMPT_RT srcu: Use rcu_seq_done_exact() for polling API ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/RCU/listRCU.rst10
-rw-r--r--Documentation/RCU/whatisRCU.rst3
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt25
3 files changed, 34 insertions, 4 deletions
diff --git a/Documentation/RCU/listRCU.rst b/Documentation/RCU/listRCU.rst
index ed5c9d8c9afe..d8bb98623c12 100644
--- a/Documentation/RCU/listRCU.rst
+++ b/Documentation/RCU/listRCU.rst
@@ -334,7 +334,7 @@ If the system-call audit module were to ever need to reject stale data, one way
to accomplish this would be to add a ``deleted`` flag and a ``lock`` spinlock to the
``audit_entry`` structure, and modify audit_filter_task() as follows::
- static enum audit_state audit_filter_task(struct task_struct *tsk)
+ static struct audit_entry *audit_filter_task(struct task_struct *tsk, char **key)
{
struct audit_entry *e;
enum audit_state state;
@@ -346,16 +346,18 @@ to accomplish this would be to add a ``deleted`` flag and a ``lock`` spinlock to
if (e->deleted) {
spin_unlock(&e->lock);
rcu_read_unlock();
- return AUDIT_BUILD_CONTEXT;
+ return NULL;
}
rcu_read_unlock();
if (state == AUDIT_STATE_RECORD)
*key = kstrdup(e->rule.filterkey, GFP_ATOMIC);
- return state;
+ /* As long as e->lock is held, e is valid and
+ * its value is not stale */
+ return e;
}
}
rcu_read_unlock();
- return AUDIT_BUILD_CONTEXT;
+ return NULL;
}
The ``audit_del_rule()`` function would need to set the ``deleted`` flag under the
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
index 53faeed7c190..be2eb6be16ec 100644
--- a/Documentation/RCU/whatisRCU.rst
+++ b/Documentation/RCU/whatisRCU.rst
@@ -15,6 +15,9 @@ to start learning about RCU:
| 2014 Big API Table https://lwn.net/Articles/609973/
| 6. The RCU API, 2019 Edition https://lwn.net/Articles/777036/
| 2019 Big API Table https://lwn.net/Articles/777165/
+| 7. The RCU API, 2024 Edition https://lwn.net/Articles/988638/
+| 2024 Background Information https://lwn.net/Articles/988641/
+| 2024 Big API Table https://lwn.net/Articles/988666/
For those preferring video:
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 30532eb7bb19..5adfe8779b61 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5672,6 +5672,31 @@
are zero, rcutorture acts as if is interpreted
they are all non-zero.
+ rcutorture.gpwrap_lag= [KNL]
+ Enable grace-period wrap lag testing. Setting
+ to false prevents the gpwrap lag test from
+ running. Default is true.
+
+ rcutorture.gpwrap_lag_gps= [KNL]
+ Set the value for grace-period wrap lag during
+ active lag testing periods. This controls how many
+ grace periods differences we tolerate between
+ rdp and rnp's gp_seq before setting overflow flag.
+ The default is always set to 8.
+
+ rcutorture.gpwrap_lag_cycle_mins= [KNL]
+ Set the total cycle duration for gpwrap lag
+ testing in minutes. This is the total time for
+ one complete cycle of active and inactive
+ testing periods. Default is 30 minutes.
+
+ rcutorture.gpwrap_lag_active_mins= [KNL]
+ Set the duration for which gpwrap lag is active
+ within each cycle, in minutes. During this time,
+ the grace-period wrap lag will be set to the
+ value specified by gpwrap_lag_gps. Default is
+ 5 minutes.
+
rcutorture.irqreader= [KNL]
Run RCU readers from irq handlers, or, more
accurately, from a timer handler. Not all RCU